Conventional elevator assemblies include one or more passenger cars that are equipped with braking blocks. The braking blocks are activated by a governor when an over-speed event occurs, i.e., when a speed of the elevator car exceeds a speed threshold. The braking blocks are assembled using a spring and an engagement member such as knurled roller or wedged block, for example. The braking blocks are progressively applied such that the engagement member pinches the guide rails to stop the elevator car while the spring cushions the deceleration.
The braking block spring typically has a fixed stiffness designed to stop the elevator car with a deceleration of approximately 1 g-force (g) when the car is at full load. Consequently, the deceleration of the car can vary depending on the number of passengers contained in the car. For example, when the engagement members are engaged and there are only a few passengers in the car, the deceleration of the car is much greater because the car is much lighter than the fully loaded case. This higher deceleration, however, can cause an unpleasant or even harsh stop for the passengers inside the car. Moreover, when the engagement member is engaged in response to an over-speed event, the car may be halted in the hoistway between floor landings. Consequently, the passengers may be confined within the car for an extended period of time before normal elevator operation is resumed.